New esters of isopropylidene glucose and process of preparing the same



United States Patent 3,171,832 NEW ESTERS 0F HSUPROPYLIDENE GLUEGSE ANDPRGQESS OF PREPARING- THE SAME Kurt Knoevenagel, Kleinlsarlhach,Grunstadt, and Roll Himmelreich, Grunstadt, Germany, assignors to C. F.Spiess dz Sohn Chemische-Fabrik, Kleinirarlhach uher Grunstadt,Rheinpfalz, Germany No Drawing. Filed .luly 18, 1960, Ser. No. 43,327Claims priority, application Germany, Early 24, 1359,

Claims. (Cl. lath-216) The present invention relates to new esters ofisopropylidene glucose and more specifically to esters of isopropylideneglucose and fatty acids. Furthermore, the present invention is directedto a process of preparing these new compounds. The products of thepresent invention are of interest as emulsifying agents and especiallyas sweling and gelatinising agents for such compounds, which contain alonger saturated or unsaturated aliphatic hydrocarbon chain with atleast 5 carbon atoms. The new compounds are of interest as intermediatesfor preparing fatty esters of glucose.

The new compounds have the general formula:

HC0 CH3 no-o cm in which R represents an acyl group of a highersaturated or unsaturated fatty acid having from about 6 to 30 carbonatoms.

The new compounds can be prepared by esterification of isopropylideneglucose by a transesterification reaction with esters of fatty acids.

The esters of isopropylidene glucose which are produced in accordancewith the process of the present invention, are suitable for use asemulsifying agents and especially as swelling and gelatinising agentsfor such compounds Which contain a longer saturated or unsaturatedaliphatic hydrocarbon chain with at least 5 carbon atoms such as forinstance petroleum ether, paraffin oils, spindle oils, esters of highersaturated or unsaturated fatty acids, esters of oleic acid and saladoil. They can be used in combination with emulsifying agents to preparepasty or liquid emulsions or suspensions especially of such organiccompounds, which contain a longer saturated or unsaturated aliphatichydrocarbon chain with at least 5 carbon atoms.

On pouring a said aliphatic hydrocarbon or an aliphatic hydrocarbonchain containing compound on the aforementioned esters of isopropylideneglucose the latter swell within a short period of time and thehydrocarbon or hydrocarbon chain containing compound is completelyabsorbed. This procedure can be compared with the process of swelling ofgelatine in water. On dissolving the esters of isopropylidene glucose inhydrocarbons or hydrocarbon chain containing compounds at raisedtemperature, the solution solidifies to a gel on cooling.

If a larger quantity of an ester of isopropylidene glucose is used, amore solid gel is obtained on cooling. The solidity or respectively thestillness of the gel depends on the quantity of esters of isopropylideneglucose used.

The quantity of an ester of isopropylidene glucose necessary forobtaining a gel with an aliphatic hydrocarbon is from about 3 toCompounds that contain a longer satuarted or unsaturated aliphatichydrocarbon group behave similarly. In some cases as for example in thecase of salad oil, the effect is favoured by adding a little water.

The following table indicates the percentage of some esters ofisopropylidene glucose which is necessary to obtain a gel which justdoes not flow at room temperature 23 (3.), when swollen in the indicatedsolvents.

GELATINISING PROPERTIES OF DIFFERENT ESTERS OF ISOPROPYLIDENE GLUCOSEIsopropyli- Isopropyli- Isopropyli- Solvent dene dene deueglucose-figlucose-G- gluc'osefistearate palmitate oleate Gasoline,petrol 0.748 10. 2 13. 2 12. 3 Spindle oils 0.915 3. 5 3. 8 Petroleumether 0.6 19. 3 24. 2 9. 7 Paraffin oil 0.876 3.7 3.1 29. 0 Methyloleate 0.872 4.1 6. 2 10. 7 Salad oil 0.925 contain mg abt. 5%

H2O 3. l 4. 3

60.5 paraiiin oil 32.0 Water 4.3 emulsifier techn. (octylphenol with 7-9ethylene oxide) 3.2 isopropylidene glucose-G-palmitate, or

40.0 water 2.85 sucrose stearate 2.85 isopropylideneglucose-6-palmitate, or

2.16 isopropylidene glucose ester from salad oil 4.32 paraffin oil 21.6paraiiin solid 71.0 water On account of their properties these newcompounds can be used as retention or evaporation retarding agents forproducts containing alphatic hydrocarbons with a chain of at least 5carbon atoms or for such compounds which contain an aliphatichydrocarbon chain with at least 5 carbon atoms.

So, for instance, a mixture of solid parafiin and test benzine (white ormineral spirits) suffers only a fifth to an eighth of the loss ofbenzine when from 2 to 5 percent of weight of an isopropylidene glucoseester are added.

The following table shows the loss of weight of a mixture of 3 grams ofparaffin and 7 grams of test benzine either without any or withdifierent amounts of isopropyh idene glucose stearate afterstanding for24 hours.

Solid Test Isopropyll- Loss of Weight paraffin, benzine, dene glucoseafter standing grams grams stearate, for 24 hours,

mg. mg.

Furthermore, the new esters of isopropylidene glucose can be used asintermediates. Thus, for example, glucose esters can be obtained fromisopropylidene glucose esters by splitting off the isopropylidene groupby acidic hydrolysis.

The present invention comprises fatty acid esters of isopropylideneglucose in which the fatty acid moiety of the esters contains from about6 to 30 carbon atoms inclusive and more desirably from about 12 to 22carbons atoms inclusive. Among the fatty acids which may constitute thefatty acid moiety of the esters of isopropylidene glucose are thesaturated fatty acids including: lauric, myristic, palmitic, stearicacids and the like and the unsaturated fatty acids including: A-dodecylenic, palmitoleic, oleic, 'ricinoleic acids and the like.

The present invention further comprises a new process for producing thefatty acid esters of isopropylidene glucose. The process comprisesreacting a non-isopropylidene glucose ester of a fatty acid (an ester ofa fatty acid with an alcohol other than isopropylidene glucose) withisopropylidene glucose.

The reaction is carried out by melting the components together withoutany solvent. The reaction mixture preferably should contain an alkalinecatalyst. The reaction is produced by melting together the reactioncomponents at temperatures of from about 150 C. up to about 220 C. Theoptimum temperature range is from about 180 C. to 200 C. The reactiontime required is usually between about 30 minutes to 6 hours.

The esters of the fatty acids employed as starting materials may besimple esters of a monohydric alcohol, such as methyl palmitate, methylstearate, ethyl laurate, methyl abietate and the like. Preferably, anester of a fatty acid and readily volatile alcohol, such as the lowermonohydric alcohols, methanol or ethanol, are employed.

The volatile alcohol is preferably stripped from the reaction mixture bybubbling an inert gas therethrough or by distillation, preferably, underreduced pressure, as it is liberated during the formation of theisopropylidene glucose ester.

The non-isopropylidene glucose esters of the fatty acids employed asstarting materials and as a source of fatty acids may also be esters ofpoly hydroxy alcohols, or polyols, where the hydroxyl groups of thealcohol are on adjacent carbons atoms, such as the diand the tri-estersof glycerol.

Among the alkaline catalysts which may be employed are hydroxides andinorganic salts such as potassium, sodium and lithium hydroxides, sodiumcarbonate or potassium carbonate and the like or such alkaline salts astrisodium phosphate. The quantity of the catalyst to be added is fromabout 0.1 to 10 mole percent.

Generally when trying to melt the various other derivatives of glucose,the products turn brown and decompose, because of their high meltingpoint. In the case of isopropylidene glucose no substantial change ofcolour becomes evident during the reaction, thus it is possible toobtain pure transesterification products and the separation of theisopropylidene glucose esters does not present any special difliculty.

It is known that when a solvent for a transesterification reaction isused it is very diflicult to get a pure transesterification productwhich does not contain any residue of the solvent used. Especially, whendimethylformamide or dimethylsulfoxide is used as a solvent it is quiteimpossible to remove the last traces of either of these solvents fromthe transesterification products. In contrast to this thetransesterification products obtained by melting of isopropylideneglucose and a fatty acid ester cannot contain any traces of a solventand therefore have a higher grade of purity.

a, Example 1 1.2-ISOPROPYLIDENE GLUCOSE-G-STEARATE 16 grams ofisopropylidene glucose, 14.9 grams of methyl stearate and 0.1 gram ofpotassium carbonate dry and well ground were melted by heating themixture up to 180 C. in an oil bath. During the heating time the mixturewas stirred and kept under reduced pressure. After heating the warmliquid mass was poured in ml. of ethyl acetate. After standing for 20minutes it was filtered and the solvent distilled off under reducedpressure. 18.1 grams of 1.2-isopropylidene glucose-6-stearate wereobtained by crystallization of the brown waxy residue from ethylalcohol. The 1.2-isopropylidene glucose-6-stearate obtained is acolourless crystalline substance which has a melting point of about 46C. to 48 C. It is only sparingly soluble in cold water, it possessesgood swelling and gelatinising properties with aliphatic hydrocarbons orwith an aliphatic hydrocarbon chain containing compound.

Example 2 LZISOPROPYLIDENE GLUCOSE-GOLEATE 11 grams of isopropylideneglucose, 14.5 grams of methyl oleate and 0.3 gram of potassiumcarbonate, dry and well ground, were melted together by heating themixture for one hour up to 180 C. in an oil bath. During the heatingtime the mixture was stirred and kept under reduced pressure. Afterheating time the warm liquid mass was poured in 100 ml. of ethylacetate.After standing for 20 minutes it was filtered and the solvent distilledoff under reduced pressure. 19 grams of 1.2-isopropylideneglucose-6-oleate were obtained in form of a light yellow coloured waxymass. The substance can be purified by recrystallization from methylalcohol. It is only sparingly soluble in cold water and possesses goodswelling and gelatinising properties with aliphatic hydrocarbons or withan aliphatic hydrocarbon chain containing compound.

Example 3 1.2-ISOPROPYLIDENE GLUCOSE-GTALMITATE 11 grams ofisopropylidene glucose, 14.5 grams of methylpalmitate and 0.15 gram ofpotassium carbonate, dry and well ground, were melted together byheating for 2 hours up to C. in an oil bath. During the melting time themixture was stirred and kept under reduced pressure. After heating timethe melt was poured in 100 ml. of methyl acetate. After standing for 20minutes it was filtered and the solvent distilled off under reducedpressure. 13.9 grams of 1.2-isopropylidene glucose-6-palmitate wereobtained in form of an almost colourless waxy mass. The substance can bepurified by recrystallization from methyl alcohol. It possesses goodswelling and gelatinising properties with aliphatic hydrocarbons or withan aliphatic hydrocarbon chain containing compound.

Example 4 ISOPROPYLIDENE GLUCOSE AND SALAD OIL 11 grams ofisopropylidene glucose, 15.7 grams of dried salad oil and 0.8 gram ofpotassium carbonate, dry and well ground, were melted together byheating for 3 hours up to C. in an oil bath. During the heating time themixture was stirred and kept under reduced pressure. Following this themelt was poured in 150 ml. of methyl acetate. After boiling withcharcoal for a short time the solution was filtered at room temperature.Then the methylacetate was distilled off and the light residue driedunder vacuum. 19.2 grams of a waxy, amber coloured mass were obtained.The substance had a saponification number of 66.3 and had goodemulsifying properties. It possesses good swelling and gelatimsingproperties with aliphatic hydrocarbons or with an aliphatic hydrocarbonchain containing compound.

We claim: 1. An ester of isopropylidene glucose of the following generalformula:

in which R represents an acyl group of a higher fatty acid having fromabout 6 to 30 carbon atoms.

2. The ester of isopropylidene glucose as set forth in claim 1 in whichR is stearoyl.

3. The ester of isopropylidene glucose as set forth in claim 1 in whichR is oleyl.

4. The ester of isopropylidene glucose as set forth in claim 1 in whichR is palmitoyl.

5. A process for the production of a fatty acid ester of isopropylideneglucose which comprises melting together isopropylidene glucose with anester of an alcohol selected from the group consisting of the loweralkanols and the lower poly hydroxy alcohols wherein the hydroxyl groupsare on adjacent carbon atoms with a higher fatty acid having from about6 to 30 carbon atoms in the absence of a solvent.

6-. The process of claim 5 in which said fatty acid ester is an ester ofa saturated fatty acid containing 6 to 30 carbon atoms.

7. The process of claim 5 in which said fatty acid ester is an ester ofan unsaturated fatty acid containing 6 to 30 carbon atoms.

8. The process of claim 5 in which said fatty acid ester is an ester ofa fatty acid containing 6 to 30 carbon atoms with glycerol.

9. A process for the production of a fatty acid ester of isopropylideneglucose which comprises melting together isopropylidene glucose with anester of a fatty acid containing 6 to 30 carbon atoms and a loweralkanol in the absence of a solvent and in the presence of an alkalinecatalyst.

10. The process of claim 5 in which said reaction is carried out at atemperature between 150 and 220 C.

References Cited by the Examiner UNITED STATES PATENTS 2,388,887 11/45Weissberger et al. 252-316 2,402,373 6/46 Cordero 252- 512 2,759,9238/56 Gibbons 260-210 2,908,681 10/59 Anderson et al. 260-234 2,931,8024/60 Touey et al. 260-234 2,992,082 7/61 OWnby et al. 260234 OTHERREFERENCES Chem. Abst. (1941 3974 LEWIS GOTTS, Primary Examiner.

J. GREENWALD, A. L. MONACELL, Examiners.

1. AN ESTER OF ISOPROPYLIDENE GLUCOSE OF THE FOLLOWING GENERAL FORMULA: